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TROPICAL STORM LILI DISCUSSION NUMBER 32
NATIONAL WEATHER SERVICE MIAMI FL
11 AM EDT SUN SEP 29 2002
AIRCRAFT FIXES OVER THE PAST 12 HOURS INDICATE LILI HAS MOVED
WESTWARD...WITH SOME WOBBLES IN THE TRACK. DEEP CONVECTION HAS
DEVELOPED AROUND THE LOW-LEVEL CENTER AND RECON DATA INDICATES AN
8-11 NMI DIAMETER EYE HAS FORMED. THE HIGHEST 850 MB FLIGHT-LEVEL
WIND REPORTED THIS MORNING HAS BEEN 57 KT...EQUAL TO ABOUT 46 KT AT
THE SURFACE...AND A MINIMUM PRESSURE OF 994 MB. UPPER-LEVEL OUTFLOW
REMAINS GOOD IN ALL QUADRANTS WHILE OUTER CONVECTIVE BANDING
FEATURES HAVE IMPROVED.
THE INITIAL MOTION ESTIMATE IS 270/06...EVEN THOUGH LILI HAS MADE A
SLIGHT WOBBLE TO THE SOUTHWEST OVER THE LAST TWO RECON FIXES. SINCE
THE LOW-LEVEL STEERING FLOW IS WEAK...LILI MAY JUST BE DOING A
SEEING-EYE TRICK BY WOBBLING JUST OFFSHORE THE NORTH COAST OF
JAMAICA. HOWEVER...ONCE LILI CLEARS THE WESTERN END OF JAMAICA...A
GOOD SOUTHWESTERLY SURGE THAT IS SEEN DEVELOPING SOUTH OF JAMAICA IN
SATELLITE IMAGERY AND QUIKSCAT DATA WILL PROBABLY ACT TO JOG THE
CYCLONE NORTHWARD A LITTLE. BEYOND 12 HOURS...LILI IS EXPECTED TO
TRACK WEST-NORTHWESTWARD AROUND THE SOUTHERN PERIPHERY OF THE
SUBTROPICAL HIGH THAT IS FORECAST TO GRADUALLY STRENGTHEN AND PUSH
WESTWARD ACROSS FLORIDA AND THE SOUTHEAST U.S. THROUGHOUT THE
FORECAST PERIOD. DUE TO THE MORE WESTWARD JOG THAT LILI HAS TAKEN...
ALL OF THE NHC MODEL GUIDANCE HAS SHIFTED WESTWARD ACCORDINGLY. THE
UKMET AND NOGAPS MODELS ARE ON THE FAR WESTERN EDGE OF THE MODEL
SUITE...WHILE THE AVN/GFS AND AVN/GFS ENSEMBLE MODELS ARE ON THE
EASTERN EDGE OF THE GUIDANCE ENVELOPE. THE GFDL IS JUST LEFT OF THE
AVN/GFS MODEL...WHEREAS THE GFDN IS CLOSE TO THE UKMET-NOGAPS
SOLUTIONS. THE OFFICIAL FORECAST TRACK WAS ADJUSTED TO THE LEFT OF
THE PREVIOUS TRACK AND IS SIMILAR TO THE GFDL IN DIRECTION...BUT
SLOWER LIKE THE AVN/GFS. AFTER 48 HOURS...THE FORWARD MOTION WAS
INCREASED TO ABOUT 11 KT LIKE THE AVN/GFS MODEL...WHICH IS THE
SLOWEST OF ALL THE GLOBAL MODELS.
THE INTENSITY FORECAST IS SOMEWHAT PROBLEMATIC. GENERALLY...WHEN A
MODERATE TROPICAL STORM DEVELOPS A SMALL DIAMETER EYE...RAPID
INTENSIFICATION USUALLY FOLLOWS. HOWEVER...THE PROXIMITY TO LAND
WILL LIKELY PRECLUDE THAT FROM HAPPENING...AT LEAST FOR THE NEXT 12
HOURS OR SO. BUT BEYOND THAT...UPPER-LEVEL CONDITIONS APPEAR VERY
FAVORABLE FOR SOME SIGNIFICANT STRENGTHENING TO OCCUR BEFORE LILI
MAKES AN EXPECTED LANDFALL OVER WESTERN CUBA. AS WAS ALLUDED TO IN
THE PREVIOUS DISCUSSION...LILI HAS THE POTENTIAL TO BECOME A
SIGNIFICANT HURRICANE ONCE IT MOVES INTO THE SOUTHEAST GULF OF
MEXICO. HOWEVER...THE OFFICIAL INTENSITY FORECAST IS NOT QUITE AS
ROBUST AS THE SHIPS INTENSITY MODEL...WHICH BRINGS LILI TO 91 KT IN
72 HOURS.
FORECASTER STEWART
FORECAST POSITIONS AND MAX WINDS
INITIAL 29/1500Z 18.7N 77.6W 45 KTS
12HR VT 30/0000Z 19.2N 78.5W 50 KTS
24HR VT 30/1200Z 20.2N 80.0W 55 KTS
36HR VT 01/0000Z 21.2N 81.8W 65 KTS
48HR VT 01/1200Z 22.4N 83.8W 70 KTS...INLAND OVER WRN CUBA
72HR VT 02/1200Z 24.5N 87.5W 80 KTS
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